Ridge grinding tool



Dec. 26, 1950 E. M. Mc ov ET AL 2,535,587

RIDGE GRINDING TOOL Filed May 1, 1948 INVENTOR. [om/A20 M. 11.40 acme/v597d PAUL SCHQ/CK Mandi 7M ATTOQNEYS Patented Dec. 26, 1950 amenGRINDING TOOL Edward M. McGovern, Maplewood, and Paul Schrick, Newark,N. J.

Application May 1, 1948', Serial No. 24,594

' 1 Claim. (01. 51-245) This invention relates to a ridge grinding tooladapted to true the borehole of a cylinder for an internal combustionengine.

It is an object of the instant invention to pro vide a simple tool fortruing'the borehole of anengine cylinder with precision.

A further object is to provide a tool of the type described that willdecrease labor requirements over prevalent practices Still anotherobject is to provide an inexpensive tool which can be readily operatedby ex isting equipment in the average shop.

Other objects of the instant invention will become apparent in thecourse of the following specification.

The imperfections or ridges in the boreholes of the cylinders ofinternal combustion engines which remain after the first manufacturingop erations or even after reasonable service must be removed to obtainreasonable engine efliciency. t

In the instant invention, such ridges or imperfections are removed withan abrasive wheel. Since any but a thoroughly controlled abrasive wheelcould do as much harm to the borehole as the ridges, the ridge grindingtool is designed to be mechanically lowered in and rotated around theborehole while a guide pin coacting with the abrasive wheel prevents theremoval of more than a predetermined amount from the wall of theborehole.

The invention will appear more clearly from the following detaileddescription when taken in connection with the accompanying drawingsshowing by way of example a preferred embodi ment of the inventive idea.

In the drawings:

Figure 1 is a top plan view of the ridge grinding tool inserted in theborehole of a cylinder of an internal combustion engine and constructedin accordance with the principles of this invention.

Figure 2 is a sectional view along the line 2-2 of Figure 1.

Figure 3 is an elevational view of the ridge grinding tool inserted inthe borehole of a. cylinder, a part of the wall of which has beenremoved.

Referring now in greater detail to the drawings in which like referencenumerals indicate like parts, reference numeral I9 indicates the ridgegrinding tool and II the cylinder.

The ridge grinding tool Ill comprises the abrasive wheel I2 and asupport formed with a lower disc I3 and an upper disc I4 for impartinglinear and angular motion to the same in the borehole of the cylinderII.

The lower disc I3 and the upper disc I4 have the same diameter and aredesigned for insertion in the borehole of the cylinder I i in a planeperpendicular to the longitudinal center line 2 thereof. At the centerof the lower disc is is the upwardly extended hub I5 of circular crosssec-'- tion, and formed integral therewith or otherwise as desired.Through the hub I5 is the aperture 22 for the insertion of the rod 23 insuch a man ner that the collar 24 of the rod '23 coacting with- I pin I!inserted through the aperture IS" in the upper disc I4 and then threadedinto a coacting tap I9 in the lower disc I3 so that the radii of theslot I6 are centered at the center of the pivot pin II, the minimumdiameter of the slot I5 being equal to the distance from the center ofthe pivot pin IT to the nearest edge of the hub I5 and the maximumdiameter being equal to the distance from the center of the pivot pin IIto the nearest edge of the hub I5 plus the diameter of said hub with dueconsideration for tolerance. Thus, the upper disc I4 is pivotallyconnected to the lower disc about the pivot pin I 1 and guided by thehuh I 5 moving in the slot I6. To one side of the pivot pin I! in theupper disc I6 is an anchor pin 20 while between the two pins is thespring member 2| designed to maintain under tension the upper disc I4 tothe right, as viewed in Figure 1, of the lower disc I3. One end of thespring.2I is located in an annular groove formed in the anchor pin 21!,while the other end is located in a transverse groove formed in thepivot pin I1. I

Substantially opposite the pivot pin I! and also along the outer rim ofthe upper disc I4 is the abrasive wheel I2 rotatably and verticallymounted thereon by any suitable means such as the shaft 26 (Fig. 2)secured at the top of the said wheel I2 by the collar 2"! and at thebase by reducing the diameter of the shaft 26. The end of the shaft 26is reduced, as shown in Figure 2, to coact with the form of the aperture23 in the upper disc 54 in which the shaft 26 is held upright by thecountersunk screw 29. The upper part of the shaft 26 is designed forinsertion in the drive 3D for imparting angular velocity to the abrasivewheel I2.

Below the abrasive wheel I2 is the guide pin 3| adjustably secured inthe holder 32, as shown in Figures 1 and 3, attached to the upper discIs by the screws 33 and 34 while the set screw 35 provides a means foradjusting the guide pin 3t relative to the abrasive wheel I2.

The operation is as follows: The ridge grinding tool Iii is lowered inthe borehole of the' cylinder H substantially as shown in the variousillustrations. The top of the shaft 26 is attached to any suitable drive30 designed to impart angular velocity thereto. The shank 36 (Fig. 2) isthen screwed into the top of the rod 23 asshown and the opposite endsecured in a drill press or the like to impart linear and angular motionto the disc l3 and I4. The abrasive wheel I2 is automatically broughtinto contact with the wall of the borehole by action of the springmember 2| forcing the upper disc l4 counterclockwise relative to thelower disc 13. Of course, prior to the insertion of the tool ID, the setscrew 35 is loosened and the guide pin 3| adjusted in the holder 32'until the tip is substantially tangent to a vertical plane in turntangent to the said wheel I2; Angular velocity is-then imparted to theshaft 25 and linear and angular motion to the shank 3B, the abrasivewheel l2'removing the ridges and imperfections with mechanical precisionwithin the limits of the guide'pin 3!.

It is apparent that the specific illustration shown above has been givenby way of illustration and not by way of limitation and that thestructure above described is subject to wide variations andmodifications without departing from the scope or intent of the presentinvention.

. What'is claimed is:

A ridge grinding tool for the boreholes of the cylinders of internalcombustion engines; the tool comprising a shaft, one end of the shaftbeing adapted for releasable insertion in the chuck of the drill press,a lower disc mounted upon the other end of the shaft; the tool furthercomprising an upper disc, means pivotally mounting the upper discadjacent the peripher of the lower disc, the upper disc having a closedslot therein receiving said shaft which extends therethrough and therotation of the upper disc on the lower disc being within the limits ofthe slot, an abrasive wheel rotatably disposed on the top surfaceportion of the upper disc, a spring member between the pivotal mountingmeans of the upper disc and said upper disc and adapted to maintain thewheel under tension against the wall of the borehole, and an adjustableguide adjacent the wheel on the upper disc and adapted to limit thedepth of the cut of the wheel, said guide projecting into a lineparallel to the axis of the shaft and passing through the outerperiphery of the abrasive wheel.

EDWARD M. McGOVE-RN PAUL SCI-IRICK.

REFERENCES CITED The following references are of record in the Name DateRoss May 193?.

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